The Science of Chronic Pain
Pain is a significant public health problem. An epidemic really. In the US alone, according to the NIH, it costs us at least $635 billion annually.
Pain and the Brain
Pain is a universal human experience that is produced by the brain 100% of the time. That’s true no matter how long you’ve had the pain and no matter what kind of pain it is. If pain has been around for longer than 6 months (enough time for structural recovery) then it's persistent, or chronic.
This is a real hardship and many people don’t know what to do about it. I think it’s useful to understand how the pain system works.
People in chronic pain aren't crazy and it’s not “all in their head." It’s a very real experience and there's a way to change it.
Here’s the science of what’s going on.
Paul steps on something prickly.
The sensation sends a quick signal to the site of the famous “pain gate” in the base of the spinal cord, the dorsal horn. The signal is shot all the way up the Thalamus and says, “there's something prickly on the bottom of the foot on the skin!” Whatever Paul stepped on was serious enough to also activate slow conducting free nerve endings, nociceptors. These communicate the message too. The message reaches the spinal cord and it says to a fresh neuron, “there’s danger in the bottom of the foot.” This neuron travels up to the thalamus and tells it about the danger. The thalamus then has to decide "IS THIS DANGEROUS?" It asks the frontal lobe of the brain.
Is This Dangerous?
In order to answer this, the frontal lobe checks in with the parietal lobe and gathers:
Meaning from beliefs, knowledge/logic, other sensory cues, social context, anticipated consequences, previous history, family, media, culture, previous exposure, finances, season...and more.
Amazingly, all of these factors inform the brain while deciding whether or not it’s dangerous, how much meaning it has and therefore how much pain to make Paul feel. Neurotransmitters are then sent back down the spinal cord with the information about the pain reaction in a process called nociception and descending modulation.
All of this happening without us knowing about it.
Yes, It's Dangerous
Back to Paul. His brain has decided he's been here before and he couldn't walk for days and it was super painful. It usually takes several danger signals to activate a response. In people with persistent pain, it’s starting to take fewer danger signals to cause the reaction...creating a hyper-sensitized system. Eventually a particular neurotag is created, the pattern of neuron activation which creates a certain output of the brain. It’s a chemical reaction and once mapped out, there’s a lot of conscious and unconscious focus in a specific area, way too much.
This is called sensitization, or the brain doing a weird thing. When pain persists, it’s less about the structural damage and more about the sensitivity of the nervous system.
Pain is Complex
The fascinating piece here is that the brain pulls from the storehouse of meaning and circumstance to output a reaction. Credibility of any threat to the body is entirely up to your brain. We only hurt when the brain assigns meaning to the data coming from the tissues.
The pain experience is real and the 80% of people that suffer from back pain at some point in their lives are innocent people that do not want to have pain.
Pain is an end result as the brain tries to protect you. The thing is, we are wired to over-react to potential threats, and so dysfunctional pain sensation is a common problem. When you're getting protection from something that you don't need anymore, ultimately, it’s not even informative and it’s unhelpful.
Studies show that low back pain is the single leading cause of disability worldwide.
Take Care of All-Around Health
Yoga Therapy as an intervention shows people in pain HOW TO interrupt this cycle. It’s powerful in showing people how to close the pain gate.
From experience I know that this takes commitment and effort. This article represents the first step, understanding the process of pain.
Persistent pain stems from the brain and it can be retrained when looked at from the perspective of the whole person.
So get help if you need it, and get started!